guys i havent been here for a while and i just stopped by and saw this thread, and, if i may
the reason this idea wont work is, as many people have explained before, that a mirror will reflect an image, but if youre passing light through it then it will counterbalance the brightness or the lcd and completly erase that image
for example, have you ever seen a two sided mirror like those in supermarkets where the security guys are in usually? they actually only work because the level of light on one side is less than on the other side, which would be, the reflective side of the mirror, if you turn on the light inside the room you can actually see a faint image of the people inside it. This is why it wont work, because if you intend to pass light through it then it stops being a mirror and acts more like a glass, even if it did work the quality of the image would be mediocre at best
i suggext you abandon this idea and stop listening to people telling you to go for it because they want someone to do the work for them, even if they know damn well that theres no way on earth this setup is going to work
the reason this idea wont work is, as many people have explained before, that a mirror will reflect an image, but if youre passing light through it then it will counterbalance the brightness or the lcd and completly erase that image
for example, have you ever seen a two sided mirror like those in supermarkets where the security guys are in usually? they actually only work because the level of light on one side is less than on the other side, which would be, the reflective side of the mirror, if you turn on the light inside the room you can actually see a faint image of the people inside it. This is why it wont work, because if you intend to pass light through it then it stops being a mirror and acts more like a glass, even if it did work the quality of the image would be mediocre at best
i suggext you abandon this idea and stop listening to people telling you to go for it because they want someone to do the work for them, even if they know damn well that theres no way on earth this setup is going to work
Why are some of you trying to disprove of jake's idea when it's perfectly fine. The way I see it is that the conventional mean of direct projection through a transmissive/transflective lcd is no different than projection by way of reflecting an opaque image. I dont wanna try and explain why they are the same but if you dont believe that then I suggest you stick to hobby thats less complicated. the only downside to this idea is that your gonna end up with a more complicated setup (therefore costing more). On the upside you dont have to rip apart an lcd monitor (which was your project's goal) and it can also project whatever you want it to project. There are some commercial products of this design available, i dont know much about them but there are some selling on ebay, try: http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&item=2359586458&category=16508.
a different approach....
I was taking a[art an lcd and playing around with the backlight when i noticed that its some sort of "spreader"for the light from the 2 foleresent bulbs. So here is my idea, why not use that filter to "spred" our lightsources across the lcd more evenly? That would help with the problem of having to move driverboards out of the way and focal lengths of parabolic reflectors. Then just put your lcd with super backlight power behind the frensel lens and boom! lcd projector. This would still require dismantling of the lcd monitor, but it would solve alot of problems too, like heat.
In theory, of course.
Tellme what yall think,
Brad
I was taking a[art an lcd and playing around with the backlight when i noticed that its some sort of "spreader"for the light from the 2 foleresent bulbs. So here is my idea, why not use that filter to "spred" our lightsources across the lcd more evenly? That would help with the problem of having to move driverboards out of the way and focal lengths of parabolic reflectors. Then just put your lcd with super backlight power behind the frensel lens and boom! lcd projector. This would still require dismantling of the lcd monitor, but it would solve alot of problems too, like heat.
In theory, of course.
Tellme what yall think,
Brad
Xo
That Artograph on e-bay is nothing but an epidiascope.
Nonciosoldi explained earlier in this thread how it works.
It shines plenty of light on the object and that reflected light gets
projected. The prism is just there to bend the light 90 degrees.
The listing on e-bay clearly states : "The Prism is specially designed for projecting a wide assortment of originals like patterns, sketches and line drawings. It is not recommended for capturing detail in photographs. "
So unless you only want to project CAD drawings , you will be very disapointed with the results.
That Artograph on e-bay is nothing but an epidiascope.
Nonciosoldi explained earlier in this thread how it works.
It shines plenty of light on the object and that reflected light gets
projected. The prism is just there to bend the light 90 degrees.
The listing on e-bay clearly states : "The Prism is specially designed for projecting a wide assortment of originals like patterns, sketches and line drawings. It is not recommended for capturing detail in photographs. "
So unless you only want to project CAD drawings , you will be very disapointed with the results.
i thought i might put my 2cents worth in here and to help clear some of this up, ok jakes idea will work and brainchild u are right about the 2way mirror with washing the image out, ok u want to know the truth? ok this idea of jakes is used in very high end crt projectors, the reason i say very high end means that they cost one hell of a fortune and there is alot of science involved to get this to a optimum state of eficientcy, they also typically use a 800w xenon bulb, do they use mirrors as in a 2 way mirror? no they dont and not fs mirror unless they want to bend the light at a right angle, so what do they use? they use what is called a polarised mirror, the light from the crt is polarised typically horizontally, the light from the light sorce is polarised vertically, the polarisers what they use is clear but when added together and reversed from each other it is just like a mirror but only the crt image can be reflected horizontally and the light passed through vertically, so in turn what u get is a crt image with a powerfull back light without the light source washing out the image, getting these polarised coatings to a perfected state is alot of work and that is where alot of science is involved, i do axctally have some of this polarised coating but it isnt of such a high grade for this aplication, where did i get? out of my lcd back light, not all have it but when light passes through it and it hits the lcd it then sees the mirror look to it and the light can only go one way, out! thats how u get the 400nit backlights in lcds, its not so much a brighter back light but the polarises they use, they also all have diffusers, so anyway thats my 2 cents worth i think jake forget the 2 way mirrors they wont work and try to find the polarised ones and do research in that cos that is how they make this kind of a reflective projector. on a last note dont use the same type of polariser as what a lcd has, u need to get a clear one horizontal and a vertical.U will also need some kind of a combiner to combine the 2 lights togther as to a 1 even sorce to projection, a difuser may be enough for this.
Best of luck
Trev
Best of luck
Trev
i'm sorry but i can't believe i'm reading this thread
here's how projection works:
you shine an immensely bright white light thru a coloured filter (i.e LCD screen) which filters out different wavelength photons according to the colours at the point where it strikes. the photons then make their way towards the display screen where they strike and are reflected to our eyes so that we may see them.
white light will NOT be filtered by a reflected image. Ever. the reflected image on the glass from the LCD will not filter the photons coming from the projector light. it's absolutely impossible. under any circumstances. ever. the white projector light will simply carry on thru the glass as if there's nothing there - because there IS nothing there
the idea of using a coated mirror however, does have some (but not much, really not much) credibility. the inital projection from the LCD onto the mirror will result in a somewhat washed out image, then the main projector light will furthur wash out the image and it is extremely unlikey that ANY of the reflected image would be carried thru to the screen as again, there is no real filtration.
LCD's work as the each lcd cell is like a piece of cellophane. it lets only one colour thru. without that sort of physical filter, nothing will work.
no offense but, i can't believe anyone even thought of it. honestly
the mind boggles 
here's how projection works:
you shine an immensely bright white light thru a coloured filter (i.e LCD screen) which filters out different wavelength photons according to the colours at the point where it strikes. the photons then make their way towards the display screen where they strike and are reflected to our eyes so that we may see them.
white light will NOT be filtered by a reflected image. Ever. the reflected image on the glass from the LCD will not filter the photons coming from the projector light. it's absolutely impossible. under any circumstances. ever. the white projector light will simply carry on thru the glass as if there's nothing there - because there IS nothing there
the idea of using a coated mirror however, does have some (but not much, really not much) credibility. the inital projection from the LCD onto the mirror will result in a somewhat washed out image, then the main projector light will furthur wash out the image and it is extremely unlikey that ANY of the reflected image would be carried thru to the screen as again, there is no real filtration.
LCD's work as the each lcd cell is like a piece of cellophane. it lets only one colour thru. without that sort of physical filter, nothing will work.
no offense but, i can't believe anyone even thought of it. honestly
the mind boggles
ir
holy ****, that must mean that front surface mirror that is a high grade and is actually a specilised product to buy yess even to scientists is a waste of time, am i right? have u done any research into projection? have u made a model? i dont think u realy know what your talking about in the negative responce u have posted, most of the stuff u are saying is simply nothing but from a person who does not understand the ways optics work, there is no way a fs mirror will wash out an image, how can it when its designed not to? lol and yess u can polarise white light and yess a polariser is a type of filter if u want to call it that
holy ****, that must mean that front surface mirror that is a high grade and is actually a specilised product to buy yess even to scientists is a waste of time, am i right? have u done any research into projection? have u made a model? i dont think u realy know what your talking about in the negative responce u have posted, most of the stuff u are saying is simply nothing but from a person who does not understand the ways optics work, there is no way a fs mirror will wash out an image, how can it when its designed not to? lol and yess u can polarise white light and yess a polariser is a type of filter if u want to call it that
well if you won't take my word for it, think about this
replace the LCD in the above diagram with a blue light with a circular template (ie to project a blue circle)
if you project a blue circle onto the mirror, then shine a white light thru as per the diagram, you will NOT get a blue circle on the screen
you'll get ONLY the white light from the projector, whilst on the mirror you'll see the image if the blue circle
you see what i'm getting at? it's absolutely impossible
the HUD glass won't help either. it simply will not work.
and might i add, i this idea DID work it would have been explored already by the people who invent projectors etc. the reason it hasn't is because it simply can't work
replace the LCD in the above diagram with a blue light with a circular template (ie to project a blue circle)
if you project a blue circle onto the mirror, then shine a white light thru as per the diagram, you will NOT get a blue circle on the screen
you'll get ONLY the white light from the projector, whilst on the mirror you'll see the image if the blue circle
you see what i'm getting at? it's absolutely impossible
the HUD glass won't help either. it simply will not work.
and might i add, i this idea DID work it would have been explored already by the people who invent projectors etc. the reason it hasn't is because it simply can't work
ir
ir, do u know what light polarising is? i dont think u fully understand what it does, also do u know who Barco is? Barco Projector corp usa? its people like u ir that make things not worth doing and maybe why people give up, if u dont think it will work to YOUR KNEWLEGE then fine, say it once then shut up like most in here, but when somone actually has found out that a pro projector system uses this design i dont think its info that u realy want to put down, i didnt invent it, as i said ask Barco, they make them not me, im only trying to help the inventive guys in here move some what forward, not put in a pile of ****! If u dont understand how somthing works then i sujest search the net (or even this forum) and find out how it works, i have just like others in here have over time, Jake will get somwhere with this, he will find a way if he is persistant, and he is, where there is a will there is a way and what he is trying is not impossible, its been made, not anymore though due to cost and technology. the link below shows what will replace and is replacing crt tech.
http://www.jvc-victor.co.jp/english/pro/dila/device.html
ir, do u know what light polarising is? i dont think u fully understand what it does, also do u know who Barco is? Barco Projector corp usa? its people like u ir that make things not worth doing and maybe why people give up, if u dont think it will work to YOUR KNEWLEGE then fine, say it once then shut up like most in here, but when somone actually has found out that a pro projector system uses this design i dont think its info that u realy want to put down, i didnt invent it, as i said ask Barco, they make them not me, im only trying to help the inventive guys in here move some what forward, not put in a pile of ****! If u dont understand how somthing works then i sujest search the net (or even this forum) and find out how it works, i have just like others in here have over time, Jake will get somwhere with this, he will find a way if he is persistant, and he is, where there is a will there is a way and what he is trying is not impossible, its been made, not anymore though due to cost and technology. the link below shows what will replace and is replacing crt tech.
http://www.jvc-victor.co.jp/english/pro/dila/device.html
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